An affirmative defense to any sex crime where the “victim” is under the age of consent is that the accused reasonably believed that the “victim” was of legal age.
In other words, the accused had a valid reason to believe that the other persons age was at, or beyond, the legal age of consent.
Again, consent is a legal term, not a factual term.
Under Illinois law, the age of consent for any type of sexual activity is, typically, 17 years.
This means anyone younger than 17 years of age cannot lawfully consent to any type of sex act involving sexual conduct.